Apparatus for heating



J1me w. N. MCCUTCHEON ET AL 1,913,170

APPARATUS FOR HEATING Filed Dec. 12, 1930 3 Sheets-Sheet 1 guvsmo kw-n mM rm June 6, 1933. w. N. MCCUTCHEON ET AL 0 APPARATUS FOR HEATING FiledDec. 12, .1930 5 Sheets-Sheet 2 I; a! I Jun 6, 1933.

' W. N. M CUTCHEON B AL APPARATUS FOR HEATING Filed Dec, 12, 1950 3Sheets-She'et 3 INVENTORS Patented June 6, 1933 UNITED STATES PATENTorrlcs WILLIAI 1i. IOOUTGHMN, OI TEOBNBUBG, AND ARCH V BI'I'TB, FALLISON rm, PENNSYLVANIA AP'PABATUB FOR HEATING Application filedDecember 18, 1830. Serial 1T0. 501321.

The present invention relates broadly to the art of combustion, and morearticularly to an apparatus for controlling t e su ply, mixing andburning of a combustible ingredient and a combustion supportingingredient.

For urposes of facilitating a description and understanding of thepresent invention it will be described in connection with the burning ofas as the combustible ingredient, but it will understood that the.utility of the invention is not limited with respect to thecharacteristic of these two types of combustion, yellow flame combustionmay be considered as the characteristic flame resulting from a mixtureof air and gas beginning at the mouth of the burner, without anyprevious air or air pro-mixing. Blue flame combustion, on the contra isusually considered as the characteristic ame resulting from a pre-mixingof the air required, or a large part of the air, and the gas, in advanceof the mouth of the burner, and the admission of the pre-mixed gases tothe combustion chamber or furnace chamber.

From a practical standpoint blue flame combustion is so employed that itis usually characterized by a localized zone of intense temperature. Wehave found, on the contrary, that yellow flame combustion, or luminousflame combustion as it is sometimes called, may be so employed as toinvolve substantially uniform heating over a very substantial area. Itis also true, of the present invention that the effective flametemperature with yellow flame combustion may be lower than thecorresponding effective flame temperature with blue flame combustion.

In heating furnaces, such for example as annealing-ornormalizingfurnaces, it is customaay to utilize a blue flame, and rovide such amesat distances which are su ciently close to enable the obtaining of thedesired temperature condition. This necessarily results in a' heating orheat treating zone having non-uniform' temperatures in differentportions of the chamber.

It is one of the objects of the present invention to provide an improvedapparatus for use under such or similar conditions 5 whereby a morenearly uniform temperature condition throughout the entire chamber canbe obtained with lower localized temperatures.

It is also customary in the art to provide 60 chambers of the generalcharacter referred to of the so-called muflle, semimuflled or baflletype. With such structures radiation from the baflle or mufllesconstitutes one of the principal sources of heat, and it is therefore 0customary to burn the fuel under such conditions that there is a veryappreciable temperature diiference on opposite sides of such aflies ormuflles.

The present invention contemplates a zone into which the combustibleingredient and the combustion supporting ingredient are delivered andwithin which partial combustion only takes place. It is one of theobjects of the invention, however, to deliver such ingredients undersuch controlled velocity and pressure conditions, and in such amountswith respect to the dimensions of the zone as not to obtain such apronounced difference in temperature conditions between such zone andthe main portion of the chamber. Thus, while it has not heretofore beenunusual to have a. temperature difference between the combustion chamberin back of the mufile or baflle and points within the furnace chamberproper of from 600 to 800 F., the present invention will usually involvea temperature difference of not appreciably over 200 F. and usuallyless.

From the foregoing, it will be apparent to so those skilled in the artthat the'present invention involves burning of fuel and air underaccurately controlled conditions, with delivery of the fuel and, airunder predetermined velocity and pressure conditions, and 05 properlyvcorrelating these factors to the physical dimensions of the partsdepended upon for forming the partial combustion zone before referredto.

In the accompanying drawings there are illustrated more or lessdiagrammatically, certain preferred embodiments of our inv tion. In'thedrawings: I

Figure 1' is a transverse sectional view through one form of furnaceconstructed in accordance with the present invention;

Figure 2 is a longitudinal sectional view along the line II-II of Figure1 illustrating one arrangement of within the furnace;

Figures 3 and 4 are detail sectional views illustrating differentembodiments of the mvention; and

Figu

a plurality of burners re 5 is a view similar to Figures 3 and 4illustrating still another formof the invention.

. Referring generally to Figures 1 and 2 of the drawings, we haveillustratedafurnace comprising a roof 2, side walls 3 and a hearth 4,these parts hereinafter being generically referred to in the claims asconfining walls regardless of their location or direction of.

- rather extreme cross sectional area and receives air from the manifold5 through a re-' stricted orifice or controlling valve 10 by means ofwhich an appreciable pressure reduction may be obtained within the airconduit as distinguished from the pressure within the manifold. In likemanner, the gas conduit may receive its supply of gas through aregulating restriction in t e form of a valve 'or orifice plate 11.

In the form of the invention illustrated in Figures 1 and 2 the variousair conduits and the various gas conduits in any given zone transverselyof the furnace are all connected to common manifolds for air and gasrespectively, these manifolds in turn receiving air and gas from anydesired source, not shown.

' By making these manifolds of fairly large cross sectional area it ispossible to maintain a suficient volume of air and gas therein tosatisfactorily feed any desired number of gas and air conduits withoutobtaining any appreciable pressure drop in the manifolds by reason ofthe quantities withdrawn therefrom by the individual conduits, and thusmaintain a substantially constant pressure differential across the valveor orifice plates provided intermediate the conduits and the manifolds.i y

In both of these figures, also, the conduits are illustrated aseffective for delivering their respective ingredients into a zone 12 atclosely ad acent lpoints. These points of discharge are both lustratcdin these figures as being below a cover member 14 which extends insubstantial parallelism to the adjacent wall,

- which is here the hearth 4, and which is s aced from the openings inthe direction of burg of the ingredients therefrom. The cover p to thusforms a definite zone intermediate the conduits themselves and the mainheatmg chamber 15. If the ingredients were delivered into such a zoneunder pressure conditions too high relative to the zone dimenslonsltlvoundesirable conditions mi result. of these would be an agitation of suchnature as to produce a relatively complete mixing and thereforesubstantially complete combustion within 7 the zone itself, and theother would be to obtain a directional flow such as to prevent partialcombustion within the zone and obtain primary combustion directly withinthe chamber 15. In accordance wlth the present invention neither ofthese conditions is desired. We therefore construct the cover member ofsuch total area with respect to, its distance from the points of discarge and the area and velocity characteristics of such points that therewill only be a partial combustion within the zone 12.

We havepbserved that with a construction of the character described,after it has been in operation for a short time, the cover'memberreaches such a temperature as to apparently be eifective for breakingdown the fuel and assisting in further combustion which is carried onoutside of the zone and directly within the heating chamber itself. Itis our belief that this heating of the cover member is due principallyto temperature conditions within the furnace chamber rather than thepartial combustion within the zone below the cover member.

By providin a lurality of such burner units within a '0 am r, it ispossible to maintain a relatively uniform temperature throughout theentire chamber, and a combustion condition which is characterized byappreciable luminosity throughout, and almost complete absence ofanything resembling localized high temperature zones. It will beapparent that the delivery of ingredients may be such that thecombustion is of the yellowflame type, the visible conditions within afurnace giving evidence of the fact that fine carbon particles aremaintained in suspension throughout the chamber insuch manner as to atleast assist in the luminous condition referred to.

For purposes of illustrating by way of example only, one specificembodiment which ght has been found to satisfactorily give the resultdesired, and for the purpose of afiording a better understanding of howthe invention may be concretely embodied, reference will be made to atypical installation. Such an installation comprised a heating chamberhaving an over-all len h of 8 ft. a width of 4 ft. and an average eightof 3 ft. Such chamber was provided with five burners of the metalconstruction heretofore described, the urners being s aced onapproximately 18 inch centers. ith this construction it will be apparentthat the heating chamber of .the furnace contained approximately 96 cu.ft., thus making each burner responsible for the heating of a volume ofapproximately 19 cu. ft. Each of the'cover members may be i 10 of anydesired configuration, but they are.

conveniently formed either of substantially square or substantiallycircular tile or other suitable material;

In the construction referred to, each tile had an area of approximately256 sq. inches, and they were each spaced from the adjacent wall 4 at adistance of 2 in. Each cover member thus provided a pro-mixing andpartial combustion zone having a volume of approximately 640 cu. in.Into each zone there was discharged a volume of fuel varying from 80 cu.ft.-to 240 cu. ft. per hour. This discharge of gas was efi'ected with apressure in the gas manifold varying from 1n. to

.6 in. of water through a gas conduit having an effective area of .533sq. in. with an orifice of 19/64 of an inch. The air, on the other hand,varied with the fuel from a minimum of 700 cu. ft. to a maximum of 2400cu. ft. per minute. 'This-discharge of air was obtained with a manifoldressure varying from 1- in. to 8 in. of water t rough a conduit havingan effective cross sectional area of 3.96 in. and containing a 1 1n.orifice. This will serve to illustrate a preferred embodiment of thepresent invention.

The results of the structure described, and 1 the relationship ofthe-parts, was such that the fuel and air were so delivered as to givepartial combustion only within each zone, the principal combustion beingcontlnued entirely exteriorly of each zone and directly within theheating chamber. As before pointed out, it is our belief that thepartial combustion within the relatively confined zonesaided by contactof raw or unmixed gas with the heated surfaces of the cover membersproduces a partial breaking up or breaking down of thehydrocarbon-content the entire chamber itself, however, beingapproximately uniform and being visually devoid of any indication ofextremely high temperature Zones or non-uniform heating conditions.

In Figure 3 there is'illustrated a slightly modified embodiment of .theinvention in which parts corresponding to the parts already describedare designated by the same reference characters as those heretoforeused, but having a prime afiixed thereto. In this embodiment the gasconduit 9' is illustrated as extended upwardly to a point intermediatethe wall 4 and the cover member 14' and provided with a flange 16. Suchan arrangement is effective for maintaining a better separation betweenthe two ingredients until their actual delivery into the zone 12', thusprecluding pre-mixing with any resultant tendency toward a blue flamecondition,

should this be desirable.

In Figure 4, the cover member 17 is illustrated as carried adjacent oneedge by a pier or support 18 having therein a fuel discharge port 19 andan air discharge port 20. In this embodiment the cover member whilespaced from the adjacent wall of the heating chamber, lies in adirection generally parallel not only to such wall, but to the direction"of discharge of the fuel and air. The relative pressure, velocity andarea conditions, however, are such that a condition similar to thatbefore described is effectively maintained.

In Figure 5 of the drawings there is illustrated a slightly modifiedembodiment of the invention in which the gas conduit 21 is adjust-ableWithin the air conduit 22 to thereby change the point of contact orinitial mixing of the air and gas. With the gas conduit discharging intothe air conduit at a'point below the plane of the hearth23. we havefound that the cover member 24 may be moved closer to the hearth, asindicated in Figure 5; Such a -construction gives a smaller dischargearea from the zone beneath the cover member and a higher dischargevelocity. The dischargevelocitv is such that the principal combustionwithin the furnace is efl'ectively distributed throughout an appreciablearea thereof.

All of the forms of our invention are characterized by one or morepartial combustion.

combustion is obtained, but regardless of thetvpe of combustion, thestructure and operation are such that there is only partial combustionwithin the zones themselves with the principal combustion exteriorly ofsuch zones. The type of combustion used will be Ill determined to alarge extent, at least, by the temperature and atmosphere conditionsdesired, the yellow flame type being usually preferable where conditionspermit its use.

While wehave herein described and illustrated certain preferredembodiments of our 5 invention, it will be understood that changes inthe construction, relationship and arrangement of the parts may be madewithout departing either from the spirit of our invention or the scopeof our broader claims.

We claim:

1. In a furnace, refractory bottom and side walls, a burner port in oneof said walls, a refractory cover member spaced from the wall andextending parallel thereto, over- A lying the port and extendingtherebeyond,

and individual conduits extending into said port for supplying air andfuel under pressure for combustion in the furnace. 7

2. In a furnace, refractory bottom and side walls, a burner port in oneof said walls, a refractory cover member spaced from the wall andextending parallel thereto, overlying the port and extendingtherebeyond, and individual conduits extending into said port forsupplying air and fuel under pressure for combustion in the furnace, oneof the conduits projecting beyond the port and having a flange betweenthe cover member and the hearth. 3. In a furnace, refractory bottom andside walls, a burner port in one of said walls, .a refractory covermember spaced from the wall and extending parallel thereto, ove'rlyingthe port and extending therebeyond, and individual conduits extendinginto said port for supplying air and fuel under .pressure for combustionin the furnace, one of the conduits having an adjustable portion wherebythe oint of initial mixture of air 40 and gas may e changed. 7

4. In a furnace, refractory bottom and side walls, a plurality of burnerports in said Walls, refractory cover members spaced 4 from the wallsand extending parallel there- 5 to, overlying the ports and extendingtherebeyond, individual conduits extending into said ports for supplyingair and fuel under pressure for combustion in the furnace, and fuel andair mains having connections with the conduits of all said ports.

In testimony whereof we havehereunto set our hands. 1

WILLIAM N. MOGUTCHEON.

ARCH V. RITTS.

